Hotchocolate validation with C#

Question

So I've been playing around with Hotchocolate lately and I made a class which gives me back a list of students, but I want to have some validation functions for it. I didn't really find anything that helps me from the official hotchocolate website.

Student.cs

public class Student
{
    [GraphQLNonNullType]
    public string Name{ get; set; }
    [GraphQLNonNullType]
    public string LastName{ get; set; }
    [GraphQLNonNullType]
    public string Picture { get; set; }
}

This is my query, which currently gives me back all students from a list.

StudentQuery.cs

public class StudentQuery
{
    [UseFiltering]
    [UseSorting]
    public List<Student> GetStudents()
    {
        return MongoDBHelper.LoadRecords<Student>(EMongoCollection.Students);
    }

}

Now my question is, how can I make a ValidationRule for a student, saying for example that a student has to at least have 3 characters for his name? Could someone be kind enough to provide me some example?

Thanks in advance.

Answer 1

HotChocolate itself does not have a integration for input validation of this kind. The framework only does GraphQL validation. So checks for invalid GraphQL queries. (e.g. Wrong Type)

If you want to use validation there are a few community libraries to choose from:

• AppAny.HotChocolate.FluentValidation - Input field HotChocolate + FluentValidation integration
• DataAnnotatedModelValidations - Data Annotated Model Validation Middleware for HotChocolate
• FairyBread - Input validation for HotChocolate (FluentValidation)
• FluentChoco - FluentValidation middleware for HotChocolate
• Graph.ArgumentValidator - Adds input argument validation to HotChocolate (DataAnnotations)

Community libraries are listed here: https://github.com/ChilliCream/hotchocolate/blob/main/COMMUNITY.md